Machine and method for comminuting products

ABSTRACT

The invention is directed to a machine comprising a cutter assembly and impeller means, in which the cutter assembly includes a plurality of circumferentially spaced knives which have inner portions located in advance of their cutter portions and the impeller means includes a pair of members which are secured together in a predetermined axial spaced parallel relationship by a plurality of intervening circumferentially spaced blades provided with curved leading surfaces whereby to cause the product to be received in the curved surfaces for travel or flow substantially tangentially therefrom against the knives for comminuting the product.

United States Patent [1 1 Urschel et al.

[ MACHINE AND METHOD FOR COMMINUTING PRODUCTS [76] Inventors: Joe R. Urschei, 202 Michigan Ave; Edgar R. Sanders, 708 Evans Ave. both of Valparaiso, Ind. 46383 [22] Filed: Aug. 6, 1973 [2]] Appl. No.: 385,964

[ June 10, 1975 Primary Examiner-Granville Y Custer, Jr.

[57] ABSTRACT The invention is directed to a machine comprising a cutter assembly and impeller means, in which the cut- [52] U.S. Cl 241/5; 241/275 ter assembly includes a plurality of circumferemiany [Sll Int. Cl. 02c 132/18 spaced knives which have inner portions located [58} Field of Search 241/5, 27, 75 Vance of thch, Cutter portions and the impeller means includes a pair of members which are secured together [56] References cued in a predetermined axial spaced parallel relationship UNITED STATES PATENTS by a plurality of intervening circumferentially spaced 990.633 4/1911 Campbell 241/275 X blades provided with curved leading surfaces whereby 1,608,717 11/1926 Bell a .1 241/5 to cause the product to be received in the curved sur- 1 3 6/1949 Koehnew 241/5 X faces for travel or flow substantially tangentially there- 3974558 Bmoks 24l/275 X from against the knives for comminuting the product. 3,170,645 2/1965 Bchnke et al 24 U275 3,174,697 3/1965 Bridgewatcr 241/275 17 Claims, 18 Drawing Figures 19 I 76 3a :5 56 l l I so 6 u l L as J 16 85 75 8'3 g 63 "i 1 as s9 I ZZZ 6'5 BI 25 2* i 0, 'gr lk\ r Go 35 I 4.4- 36 I 3 31 v G2 4 a u as 1 a: 26 as JIZTI Ill g 33 35 71 1 6 *5 I II 7 +3 4+ Y I I I ll 32 31 SHEET PATENTEDJUH 10 ms PATENTEDJUH l 0 I975 SHEET MACHINE AND METHOD FOR COMMINUTING PRODUCTS The invention relates generally to a machine and/or method whereby certain products can be comminuted or reduced in size more efficiently than heretofore.

More particularly, the invention involves providing a cutter assembly or head comprising a plurality of circumferentially spaced knives having inner portions which are tilted or inclined fowardly and an impeller means comprising a pair of members or plates which are fixedly secured together in a parallel relationship by a plurality of circumferentially spaced blades which are provided with curved leading surfaces which serve to receive or pick up a product for travel or flow outwardly and forwardly in appreciably tangential direc tions for engagement with the inner portions of the knives for comminuting certain products which cannot be satisfactorily comminuted or conditioned by the ma chines exemplified, for example, in the Joe R. Urschel et al. US. Pat. Nos. 3,251,389 and 3,251,557.

More explicitly, in the above Patents, there is disclosed, among other things, machines comprising cutter heads having knives provided with leading planar surfaces which are disposed radially and impeller means having blades provided with radial leading surfaces. Such machines have proven most efficient for conditioning, comminuting or reducing the size of certain products such as, for example, a First Group which includes, rice, coffee, beans, peanuts, and apples as set forth in the Patents, but other products such as, for example, a Second Group including potato starch, dry corn solids, bacon rinds, cow hide, various spices, and seeds and a majority of the plastics presently commercially available cannot be satisfactorily reduced to a desirable size by utilizing the machines disclosed in the patents. Otherwise, the Second Group of products including those in the First Group can be satisfactorily and efficiently comminuted by utilizing the attributes of the machine and/or method disclosed in the subject application.

Attention is directed to the fact that in the operation of the machines disclosed in the above Patents, when any product, is for example, rotated by an impeller means at a speed of 1 1,000 revoltuions per minute in a cutter head having an inside diameter of 6 inches, the product has a tangential speed of 288 feet per second. If the product is moving outward at a radial speed of two-thirds the tangential speed, the product will move radially at a speed of 192 feet per second or 131 miles per hour. At this appreciable radial speed utilized in the Patented machines, any product tends to drive itself between the openings or spaces between the knives of the cutter assembly and at the same time, when referring to certain products such as those listed in the Second Group, the products impinge themselves on the narrow inner faces of the knives and adhere thereto and considerable motor power is required to remove the product from these inner portions of the knives. Both of these two actions are detrimental to the processing of any product, but especially to those listed in the Second Group and these adverse conditions are substantially eliminated by locating the knives of the cutter assembly and the leading faces of the blades of the impeller means substantially as depicted in FIG. 14 of the draw- %n view of the foregoing and more explicitly one of the important objects of the subject invention is to pro vide a cutter assembly in which the knives thereof have inner and outer portions, and the inner portions are located in advance of the outer portions and particularly so that the leading planar surfaces of the knives are inclined rearwardly whereby to primarily receive the product during its rotation by the impeller means and the inner narrow faces of the knives are inclined outwardly and forwardly with reference to the impellers rotation so as to substantially prevent the product from engagement therewith in order to alleviate the adverse condition of adherence of the comminuted product against the aforesaid inner faces. in other words, it may be stated that the inner faces of the knives are disposed to provide clearance to substantially prevent contact of the product therewith.

A significant objective of the invention is to provide an impeller means of the character above described in which an upper member or plate thereof is provided with a centrally located truncated conical tubular portion through which the product to be conditioned or comminuted is introduced into a central product receiving area of the impeller means defined by these members and the blades fixed there between, the purpose of which is to efficiently guide and so control the flow of the product into the receiving area that packing thereof is substantially eliminated. The members and blades also serve to efficiently control the outward flow 0f the material from the impeller means.

A specific but important object of the invention is to provide an impeller means in which its plate members and the blades are preferably notched whereby these components jointly support or carry tip elements over which the product finally flows for engagement with the knives. More specifically, the elements are sup ported by portions of the members and blades which extend outwardly from the peripheries of the members.

A particular object of the invention is to provide an improved method whereby a product may be caused to rotate and travel in curved paths, substantially in tangential directions, by centrifical force.

The invention also includes providing a machine embodying improved principles with respect to design and construction, assembly and disassembly of the components whereby to facilitate replacement and maintenance when required, stability, durability, efficient operation and tremendous capacity of output with a view to providing a resultant product which is substantially uniform in size, texture and its original identity is maintained.

Additional objects and advantages or attributes of the invention or inventions will become apparent after the description hereinafter set forth is considered in conjunction with the drawings annexed hereto.

In the drawings:

FIG. 1 is a side elevational view of a machine for conditioning or comminuting a product, with portions or the machine in section to illustrate the structural relation of its components;

FIG. 2 is an enlarged vertical section which is primarily depicted to show the operative relation of a cutter assembly and an impeller means constituting components of the machine;

FIG. 3 is a top view of the cutter assembly, with portions in section, taken substantially on line 3-3 of FIG.

FIG. 4 is side elevational view of the cutter assembly shown in FIG. 3;

Flg. S is an enlarged vertical section taken substantially on line 55 of FIG. 3;

FIG. 6 is an enlarged partial sectional view taken substantially on line 66 of FIG. 3;

FIG. 7 is a perspective view of one of a plurality of circumferentially spaced members or knives of the cutter assembly;

FIGS. 8 and 9 are modified forms of members or knives which may be utilized in lieu of the knives or members shown in FIG. 7;

FIG. 10 is a top view of the impeller means, with a portion thereof broken away to illustrate structural details;

FIG. 11 is a transverse section taken substantially on line l111 of FIG. 10;

FIG. 12 is a partial side view of the impeller means as viewed from the arrows 12-12 in FIG. 10',

FIG. 13 is a partial transverse section taken substantially on line 13-13 of FIG. 10',

FIG. 14 is an enlarged partial horizontal section taken through the cutter assembly and impeller means, with a product being conditioned or comminuted;

FIG. 15 is a view depicting the impeller means with a cutter assembly shown in FIG. 14, including a vector diagram, and a cutter assembly of a different character, for comparative purposes;

FIG. 16 is a sectional view showing the cutter assemblies shown in FIG. 15 and a different form of an impeller means with blades having radial surfaces, including a vector diagram for purposes of explaining a principle of operation;

FIG. 17 is an enlarged microscopic view of a representative sample of a product produced by the use of the impeller means shown in FIG. 16 with the tilted knives of the cutter assembly shown in FIG. 14', and

FIG. 18 is an enlarged microscopic view of a representative sample of a resultant comminuted product obtained by utilizing the structure shown in FIG. 14, which product when compared to that shown in FIG. 17 is more uniform as to size.

Referring more particularly to FIGS. 1 and 2 of the drawing, there is shown a stationary cutter assembly generally designated 1 and an impeller means generally designated 2 which is mounted in the cutter assembly for rotation by a power means, such as an electric motor 3. The motor is mounted on a suitable table or framework 4 and has a depending drive shaft 5 which is operatively connected by a belt 6 to a driven shaft 7 depending from the impeller means 2 and preferably housed in an enclosure 8 to promote safety and sanitation since a portion of the enclosure extends horizontally through an opening provided therefor in a vertical substantial cylindrical discharge guide or chute generally designated 9 which is carried by the framework and serves to control the flow and discharge of the resultant comminuted product to a container, not shown, located below the guide.

The guide may be designed and constructed in various ways but as shown, it is preferably comprised of a center cylindrical section 10, an upper or top truncated section 11 having an inner annular portion forming a central round opening 12 and a recess 12', and a flanged lower or bottom conical section 13 provided with a center discharge opening 14. A pair of seals 15 and 16 are preferably respectively interposed between the center section 10 and upper section 11 and between the center section and the lower section 13, and

a plurality of fastening means 17, of which one is shown in FIG. 1, are utilized to detachably secure the center and lower sections and compress the seal 16 there between and the upper section 11 is preferably held in relation to the center section and to an upper ring 38 of the cutter assembly by a plurality of fastening means having knobs 19, of which two are shown in FIG. 1 and one in FIG. 2. The seal 15 between the upper and center sections of the guide is obviously compressed when the fastening means 19 is tightened. The seals prevent escape of the resultant product and/or any fluids emanating therefrom.

With the foregoing in mind, the structure employed to support the impeller means 2 will now be described, followed by a description of the cutter assembly 1 and its mounting means, and a detailed description of the impeller means.

The framework 4, above referred to, is preferably provided with an upper stationary member 20 having an opening 21 therein through which the driven shaft 7 extends. A vertical tubular support 22 is carried by the stationary member 20, the latter of which extends into the guide 9 since it constitutes an upper wall of the enclosure 8. This support 22 is provided with a bore in which the driven shaft 7 is journalled. The upper end of this shaft carries a flat round head 23 upon which the impeller means 2 is mounted for rotation therewith. The connection of the impeller means to the driven shaft may be accomplished in any mode desired but as depicted a lower member generally designated 24 of the impeller means is preferably provided with a center operture 25 countersunk at 26 and with diametrically disposed bottom axially extending recesses 27 which accommodate diametrically disposed dowels or pins 28 which are fixedly carried by the head 23 for keying the impeller means 2 thereto. Fastening means, preferably in the form of a bolt 29, is also utilized to secure the impeller means to the head. This bolt has an inner end which is fixedly secured to the head and extends upwardly through the center aperture 25 and a nut 30 is threadedly connected to an upper end of the bolt with a relatively large washer 31 being interposed between the nut and an upper planar surface of the lower impeller member 24.

The cutter assembly 1 and means for supporting or mounting it will now be described. The vertical tubular member 22, above referred to, not only serves to support the driven shaft 7 and impeller means carried thereby, but also serves to support the cutter assembly. More particularly, the upper extremity of the tubular member 22 is preferably provided with a plurality of circumferentially spaced upturned angularly disposed portions or brackets 32 which carry an integral annular support 33 upon which the cutter assembly is mounted. This support is provided with a plurality of circumferentially spaced threaded apertures 34, one of which is shown in FIG. 2, for receiving screws 35 which extend through circumferentially spaced countersunk openings 36 provided therefor in a lower annular clamping member 37 of the cutter assembly for detachably fixedly securing the latter to the support 33, all of which will be more fully described hereinafter.

The cutter assembly 1 may be designed and contructed in various ways but as depicted in FIGS. 2 through 7 it is preferably comprised of the upper clamping member 38, above referred to, and a lower annular clamping member 37. This assembly also includes a lower annular ring 39 which is connected to the lower clamping member 37, an upper annular ring 40 which is connected to the upper clamping member 38 and a plurality of circumferentially spaced knives, generally designated 4], which are interlocked between these rings through the agency of the clamping members 37 and 38. This assembly further preferably includes cylindrical abutment means, generally desig nated 42 which is also clamped between the clamping members 37 and 38.

More particularly. the lower clamping member 37 is also provided with: an inner annular recess or rabbet 43 which receives the lower ring 39, a plurality of circumferentially spaced countersunk openings 44 located between the spaced openings 36, and with a plurality of dowels or pins 45 which extend upwardly from the base surface of the rabbet 43 for disposition in circumferentially spaced holes 46 which extend upwardly from the under surface of the lower ring 39 for locating purposes and fixedly securing this lower ring and the lower clamping member against relative rotation. The lower ring 39, as best depicted in FIGS. 5 and 6 is provided with a pair of concentrically disposed upwardly extending annular formations 47 and 48 separated by an annular center recess or groove 49, and with an outer annular rabbet S0. The annular formations are respectively provided with aligned notches 51 and 52 and a resilient ring 53 is seated in the center recess 49. The knives 41, above referred to. are preferably substantially in the form of rectangular prisms, as will be hereinafter described, and their lower ends are seated in the notches 51 and 52 and bear against the ring 53 whereby to distort the latter, so as to cushion and prevent vibration of the knives. The upper ring 40 is provided with circumferentially disposed notches 54 which receive the upper ends of the knives 41 and with circumferentially spaced holes like the holes 46 in the ring 39 for receiving dowels 56 carried by the upper clamping member 38 for locating purposes and preventing relative rotation between this member and the ring 40. The dowels 56 are secured in holes 55 provided in the clamping member 38. This ring is also provided with an external rabbet 57, similar to the rabbet 50 provided in the ring 39. It should be observed that the upper clamping member 38 is also provided with an inner rabbet 58 and that the lower and upper rings 39 and 40 are respectively seated in the rabbets 43 and 58 and thereby impart stability to the rings.

The abutment means 42, above referred to, also serves to impart stability to the knives and is preferably in the form of what may be called a cylindrical cagelike structure having a pair of substantially corresponding annular ring formations 59 and 60 which are fixedly secured in an axially spaced relation by a plurality of circumferentially spaced axially extending portions or posts 61. The ring formations 59 and 60 have inner portions which are respectively seated in the rabbets 57 and 50 provided in the rings 40 and 39 and engage or abut the upper and lower extremities of the knives 41 for stabilizing and positively preventing accidental outward radial displacement of the knives.

AS exemplified in FIG. 2, the lower clamping member 37 is preferably detachably connected to the annular support 33 by the screws 35 and the upper and lower clamping members are detachably connected together by the use of a plurality of circumferentially spaced fastening means, preferably in the form of four bolts 62, which extend through the openings 44 in the lower clamping member and through openings 63 provided therefor in the upper clamping member 38. These bolts at their lower ends have heads 64 which are seated in countersinks 44' and their upper ends are provided with axially threaded holes 65 which receive lower threaded extremities of four studs 66 and nut portions 67 integral with these studs serve to clamp the clamping members together in a predetermind axial spaced relation which is determined by the lengths of the bolts 62. The studs also have upper integral threaded extremities to which the knobs 19 are connected. A plurality of four bolts 66' are also utilized to secure the clamping members together.

An annular portion 68, as best shown in FIG. 2, is preferably fixed to the brackets 32 and is provided with an upper annular recess 69, a plurality of circumferentially spaced transverse apertures 70 and an outer annular groove 71. An annular abutment 72 is held in the recess 69 by a plurality of fastening means preferably in the form of bolts 73 which are anchored to the abutment 72 and extend downwardly through the apertures 70, with nuts 74 for detachably locking the abutment in place so that an outer peripheral surface thereof will abut or engage the lower ring 39 as well as the lower extremities of the knives 41. An annular gasket 75 is disposed in the groove 71 for engaging an inner surface of the lower clamping member 37 for sealing purposes.

The machine structure depicted in FIG. 2 also shows a top or cover member generally designated 76 provided with a centrally disposed tubular entrance or feed tube 77 through which the product is introduced to the impeller means and cutter assembly for conditioning, comminuting or size reduction. The underside of this cover member is provided with: a relatively large central annular recess 78, a lower annular recess 79 disposed in concentric relation to the central recess 78; an outer annular recess 80 and a plurality of circumferentially spaced apertures 81, of which one is shown through which fastening means, preferably in the form of bolts 82, fixed to an annular abutment 83, extend for detachably holding the latter in the recess 79 and against the upper ring 40 and upper ends of the knives 41. Otherwise expressed, a portion of the upper clamping member 38, upper ring 40 and upper ends of the knives are disposed in the outer annular recess 80, all for the purpose of locating and interlocking the compo nents whereby to impart stability thereto. The large central recess 78 in the cover member serves to provide clearance for an upper truncated conical portion 84 of the impeller means 2. It should be observed that the conical portion 84 is provided with a relatively large opening 85 and that this opening is so located that a portion 86 of the cover 76 is disposed therein so that the product to be comminuted will freely flow directly into the impeller means and thereby prevent spillage in the entrance area. It should further be observed that the portion of the upper section 1 1 of the guide 9 defining the opening 12 therein is supported on the upper clamping member 38 and that the cover 76 and the upper section 11 are jointly locked in place upon the cutter assembly by the knobbed fastening means 19, above referred to, which are threadedly connected to upper extremities of the studs 66.

The character of the knives 41 will now be described. As alluded to above, these knives are preferably constructed in the form of rectangular prisms and one is depicted in FIG. 7. More specifically, each of the knives 41 preferably includes a relatively large planar leading surface 87 and a corresponding trailing surface 88, an inner relatively narrow rectangular planar face or surface 89 and a corresponding outer narrow rectangular surface 90, and upper and lower end surfaces 91 and 92. In view of the duality of the surfaces the knives may be reversibly installed between the rings 39 and 40 so as to enhance their life.

As illustrated in FIGS. 14 and 15, there is shown a plurality of the knives 41 which are preferably disposed generally chordally or in planes which are inclined in a direction opposite to the rotation of the impeller means or to express it in another way, the knives are tilted backwardly so that their inner portions which are nearest to the impeller means are located in advance of their outer portions. The blades 41 shown in FIG. 15 are identified as a group 15-A and there is also shown a group 1SB of knives 41' which correspond in shape to the knives 41 but have trailing surfaces 93 which are disposed radially as disclosed in the above identified Joe R. Urschel et al. patents, as distinguished from the chordally disposed knives 41 for comparative purposes. The impeller means 2 is primarily intended for use in combination with the knives 41 in group 15A but may also be employed with a cutter assembly having knives like 41'.

In FIG. 16 there is shown a group 16-A of knives 41 which correspond to the group l5-A, a group l6-B which correspond to the group B, and an impeller means generally designated 200 having blades 201 provided with a leading surface 202. The knives 41' and impeller means 200 are substantially the same as those disclosed in the above Patents. As noted above when the impeller means 200 is utilized with a cutter assembly having knives 41' the resultant comminuted product appears substantially as presented in FIG. 17, but when the impeller means 2 is employed with the cutter assembly I having the tilted knives 41 the resultant product has proven to be more uniform and superior as exemplified in FIG. 18. The operative relationship of the knives with respect to the impeller means 2 will be explained more in detail subsequently after the impeller means 2 is described.

The impeller means exemplified in FIG. 10 through 14 embodies improved principles of design and construction and preferably includes an upper member generally designated 94 and the lower member 24, above referred to, which are secured together in a predetermined axially spaced parallel relation by a plurality of circumferentially spaced blades 95. This impeller means may be of any size desired but is preferably of a size for rotation within a cutter assembly having an inside diameter of 6". More specifically, the upper member 94 includes a planar annular or round portion 96 provided with a plurality of preferably nine circumferentially spaced outwardly extending abutments 97 and the lower member 24 is provided with a planar an nular or round portion 98 having a plurality of nine outwardly extending abutments 99, all of which substan tially respectively correspond to the annular portion 96 and abutments 97 of the upper member. The upper member 94 also includes the truncated conical portion 84, above referred to. The lower member 24 also preferably includes a relatively thick central portion 100 as shown in the FIGS. 2 and l l, which portion is provided with the central aperture 25 and countersink 26 which respectively receive the bolt 29 and the dowels 28 for fixedly securing the impeller means to the head 23 of the driven shaft 7 as set forth above.

It is to be observed that the corresponding abutments 97 and 99 of the upper and lower members 94 and 24 of the impeller means are preferably notched as indicated at 101 and that outer portions of the blades 95 extend outwardly beyond the abutments 97 and 99 and are provided with notches 102 which are generally aligned with the notches 101 and serve to position and accommodate hardened tip elements 103 which are fixedly secured in the notches. It is also to be noted that the axial distance between the members of the impeller means is determined by the blades 95 and that these blades, due to their size and structure, serve to support the elements 103 and reinforce or stabilize the respective positions of the components constituting the impeller means.

As set forth above, one of the principal objectives of the subject invention is to provide an impeller means of the character just described and one of its significant features of construction resides in the blades 95 which are preferably substantially arranged chordally. These blades may be further described as having outer portions which are located in advance of their inner portions, and being provided with curved leading surfaces 104. These blades may be secured at any desired angles and the leading surfaces 104 of the blades may be modified within practical limits. For example, as shown in FIG. 15 the curvature may be of a progressively lesser magnitude as indicated by the dotted lines 106 or 107 or the curvature may be of a greater magnitude than that illustrated. The impeller means may be operated at any desired speed of rotation but is preferably rotated with a range of between 8,000 and 12,000 R.P.M.

The upper and lower members of the impeller means are substantially of the same diameter and extend substantially radially outward to the ends of the impeller blades as well as substantially to the knives 41, the purpose of which is to direct the product outwardly under the full control of the impeller means without having the product rub or frictionly engage at high speed against any stationary parts which could cause melting or burning of the product. Such equipment has proven very successful in commercial use since a superior resultant product is obtained as exemplified in FIG. 18 as compared to the resultant product shown in FIG. 17.

The tip elements 103, above referred to, may be designed and constructed in various ways, but as shown particularly in FIG. 15 they are generally in the form of rectangular prisms and have portions which are secured in the notches 101 and 102 and outer portions which project outwardly beyond outer surfaces 108 of the blades and are preferably provided with bevelled surfaces 109 to provide clearance and with leading sur faces 110 which intersect the surfaces 109 at lines or points 111, the latter of which are preferably located at a running clearance distance of 0.008 inch from innermost cutting edges 112 of the knives 41. The leading surfaces 110 of the tip elements are preferably disposed at the angles in the neighborhood of l0 with reference to the radial lines of the impeller means. It should be observed that the elements project outwardly from the peripheries of upper and lower members of the impeller means so that their leading surfaces are offset and serve to finally direct the product outwardly and forwardly only against the edges 112 and leading surfaces 87 of the knives. It should be further observed that the knives 41, due to their tilted positions, locates their inner narrow faces 89 in positions of relief whereby a product, such as the one identified as 113 in FIG. 14, will be caused to engage only the cutting edges 112 and the leading surfaces 87 of the knives and not the faces 89, thereby providing a meritorious advance in the art and overcoming the detrimental factors, above referred to, by substantially preventing at least certain products being comminuted from accumulating and forming solid deposits of matter or residue on inner portions of the knives.

Referring again to FIG. 16 of the drawings. attention is directed to the fact that this FIGURE among other things, is presented for the purpose of explaining a principle. As shown the impeller means 200, above referred to, is provided with a plurality of circumferentially spaced corresponding blades of which one designated 20] is depicted as having a leading surface 202 ofa predetermined radial extent. If this blade was extended to the center of the impeller and a ball was placed near this center, rotation of the impeller would cause the ball to roll outwardly along the surface 202 due to centrifugal force. Mathematical calculation and actual testing confirm the principle that when the ball reaches the outer end of the blade that the radial speed of the ball will be exactly the same as the tangential speed so that the ball will leave the end of the blade or impeller at an angle of 45 to either the radial line or the tangen tial line when referring to any stationary part over which the impeller is rotating. This angle of 45 is shown by the dotted lines 203 of the vector diagram. However, if the impeller blade does not extend or reach to the center of the impeller as shown by the full line in FIG. 16, when a ball or a piece of a product reaches the outer end of the impeller blade the radial speed will be less than the tangential speed, but this radial speed will be substantial. This is illustrated by the full line 204 of the vector diagram which shows the angle formed by movement of the product and the tangential line to be less than 45. As alluded to above, when processing certain products, the impeller is rotated at 1 1,000 r.p.m. inside a cutter assembly or cutting head having an inside diameter of 6 inches. When the product reaches the outer end of the impeller blade as shown in FIG. 16, the product is moving outwardly at a radial speed of two-thirds the tangential speed, the product will be moving radial at a speed of 192 feet per second or 131 miles per hour. At this radial speed, certain products tend to drive themselves between the openings or spaces between the knives of the cutter assembly or cutter head and at the same time these products will impinge themselves on inner narrow faces of the blades 41' so as to adhere thereto and considerable motor power is required to remove the product from these faces. Both of these two actions are detrimental to the processing of certain products.

Referring again to FIGS. 14 and 15, when the product 113 moves outwardly along the curved leading surface 104 of the impeller the tangential speed of the product is increased and the radial speed of the product is decreased as shown by the vector diagram in FIG. 15. When the product strikes the knives 41 of the cutter assembly 2, it strikes them more nearly at a tangent to the circle as compared to the configuration or structure shown in FIG. 16. The product is, therefore, not driven between the knives and is not impinged upon the inner narrow faces of the knives and, therefore, the two adverse or detrimental conditions resulting from the use of the impeller 200 with the blades 41' are substantially eliminated.

Products such as those listed above in the Second Group cannot be reduced in size to a desirable degree by the Patented structures, above referred to, and the reason for this is that small amounts of friction during the cutting process will either cause these products to melt or burn. To overcome this problem or disadvantage, the structure illustrated in FIG. 14 is utilized which demonstrates that the product 113 does not rub against the inner narrow faces 89 of the knives 41 but engages only the leading surfaces 87 and the innermost cutting edges 112 of the knives.

A product such as Teflon which has low friction characteristics and a high melting point can be successfully reduced in size by utilizing the impeller means 2 either with a cutter head having the knives 41 or 41. However, Teflon cannot be reduced in size successfully by using the Patented structures.

As explained above, the knives 41 are tilted or so arranged that their inner narrow faces 89 are disposed to provide relief to prevent the product from engagement therewith. This objective may also be obtained by providing cutter assemblies having knives such as 300 and 400 which are respectively disclosed in FIGS. 8 and 9. These modified knives may be disposed so that their leading faces are on radial lines. More specifically, the knife 300 is preferably provided with beveled inner narrow face 301 and the knife 400 is shown provided with inner pointed projection 401 which extends inwardly beyond an inner face 402 so that the product will only engage its leading surface 403 and not its inner face 402. It is to be understood that knives such as those shown in FIG. 8 of the above US. Pat. No. 3,251,557 may be utilized in lieu of the knives 41.

In view of the foregoing it should be manifest that accummulation of residue or matter into very hard solids on the inner surfaces of the knives during the process of comminuting is substantially eliminated by utilizing the impeller means 2 in combination with either the blades 41 or 41'. More specifically, in this respect, the foregoing advantage is achieved by providing the blades of the impeller means with curved leading surfaces and/or by tilting the knives backwardly whereby the product is first directed forwardly in substantially maximum tangential directions against the cutting edges of the knives where it is cut into fine particles of substantially uniform size for flow outwardly through the spaces between the knives.

Attention is directed to the fact that with some products, pieces of the cut product may remain between the knives of the cutter assembly and these pieces may accummulate there until the openings or spaces between the knives are plugged tight. To overcome this tendency, air is drawn down into the machine through the feed hopper and from the inside of the cutter assembly to its outside in order to blow out any pieces of cut material that may tend to lie in the spaces between the knives. This blowing out is accomplished through the agency of an air pump but is not disclosed or claimed in the subject application.

Having thus described our invention or inventions, it is obvious that various modifications may be made in the same without departing from the spirit of the invention and, therefore, we do not wish to be understood as limiting ourselves to the exact forms, constructions, arrangements, and combinations of the parts herein shown and described.

We claim:

1. in combination: a cutter assembly having a plural ity of circumferentially spaced knives having inner cutting edges and impeller means comprising a pair of substantially round planar members, a plurality of circumferentially spaced blades interposed between and carried by said members, said blades having inner leading surfaces disposed within the confines of said impeller means and with outer leading surfaces extending outwardly and forwardly at an angle with reference to said inner surfaces for directing a product introduced into the impeller means against said cutting edges, and said knives also having outwardly extending surfaces and inner faces which are disposed to provide clearance whereby the product is caused to first substantially engage said cutting edges for cutting the product into fine particles and so that the latter will flow outwardly between said knives via said extending surfaces and substantially avoid engaging said inner faces.

2. The combination defined in claim 1, in which said outwardly extending surfaces adjacent said cutting edges are inclined rearwardly.

3. In combination: a cutter assembly and an impeller means disposed therein for rotation, said cutter assembly comprising a plurality of circumferentially spaced knives, said impeller means comprising a pair of planar round members and a plurality of spaced blades joining said members at circumferentially spaced locations and defining in combination with said members an internal product receiving area, one of said members being provided with a central opening through which a product may be introduced into said receiving area, and said blades being respectively provided with concave leading surfaces and with leading surfaces facing in the direction of the impellers rotation which extend outwardly with reference to said concave surfaces whereby to cause the product to travel for substantially maximum tangential discharge from said impeller means against said knives for comminuting the product for flow outwardly from said assembly through the spaces between said knives.

4. In combination: a cutter assembly having a plurality of circumferentially spaced knives provided with relatively large outwardly extending surfaces and inner smaller surfaces defining cutting edges and impeller means comprising a pair of planar round members and a plurality of spaced blades joining said members at circumferentially spaced locations and defining in combination with said members an internal product receiving area, one of said members being provided with a central opening through which a product may be introduced into said receiving area, and said blades being respectively provided with concave leading surfaces and outer surfaces extending outwardly with reference to said concave surfaces and facing in the direction of the impellers rotation whereby the product upon rotation by said impeller means will be caused to engage said cutting edges for cutting the product into fine particles for discharge outwardly along said extending surfaces and between the spaces between the knives and free of the cutter assembly without substantially engaging said inner surfaces.

5. in combination: a cutter assembly and an impeller disposed therein for rotation, said cutter assembly comprising a plurality of circumferentially spaced knives provided with inner cutting edges and with outwardly extending surfaces which are tipped backwardly with respect to the impellers rotation, said impeller comprising a pair of planar round members and a plurality of spaced blades joining said members at circumferentially spaced locations and defining in combination with said members an internal product receiving area, one of said members being provided with a central opening through which a product may be introduced into said receiving area, and said blades being respectively provided with leading surfaces which are curved in the direction of rotation and with leading planar surfaces which extend outwardly with reference to said curved surfaces and face in the direction of the impellers rotation whereby to cause the product to travel substantially tangentially against said cutting edges for comminuting the product into fine particles of substantially uniform size for flow outwardly along said extending surfaces and through the spaces between said knives from said cutter assembly.

6. In combination: a cutter assembly and an impeller disposed therein for rotation, said cutter assembly comprising a plurality of circumferentially spaced knives which have inner cutting edges and outer portions which are tipped backwardly with respect to that of the impellers rotation, said impeller comprising a pair of planar round members and a plurality of blades joining said members at circumferentially spaced locations and defining in combination with said members an internal product receiving area, one of said members being provided with a central opening through which a product may be introduced into said receiving area, and said blades being respectively provided with outer leading surfaces which face in the direction of the impellers rotation and with inner leading surfaces for causing an introduced product to travel outwardly in advance of said outer surfaces for engagement thereby whereby the latter direct the product against said cutting edges for comminuting the product into line particles for flow outwardly through the spaces between said knives.

7. The combination defined in claim 6, in which said knives are provided with inner faces disposed to provide clearance so that the product will substantially only engage said cutting edges and avoid said inner faces.

8. in combination: a cutter assembly and an impeller disposed therein for rotation, said cutter assembly comprising a plurality of circumferentially spaced knives which have inner cutting edges and outer portions which are tipped backwardly with respect to that of the impellers rotation, said impeller comprising a pair of planar round members and a plurality of blades joining said members at circumferentially spaced locations and defining in combination with said members an internal product receiving area, said blades having outer portions which extend outwardly relatively short predetermined distances from the peripheries of said members and said members are provided with portions which also extend outwardly beyond their peripheries for supporting and reinforcing said outer portions of said blades, one of said members being provided with a cen tral opening through which a product may be introduced into said receiving area, and said blades being respectively provided with leading concave surfaces which are curved forwardly with respect to the impellers rotation whereby to cause all of an introduction product to first travel on said leading surfaces and then substantially directly against said cutting edges for comminuting the product into fine particles for flow outwardly through the spaces between said knives.

9. Am impeller means adapted for use with a cutter head to assist in comminuting a product, said impeller means comprising a pair of planar round members and a plurality of blades joining said members at circumferentially spaced locations and defining in combination with said members an internal product receiving area, one of said members being provided with a central opening through which a product may be introduced into said area, and said blades being respectively provided with inner surfaces which are curved in the direction the impeller means rotates and with outer offset leading surfaces extending outwardly with reference to the periphery of said impeller means whereby an introduced product upon rotation of said impeller means will be caused to travel outwardly in paths successively along said curved and offset surfaces for substantially maximum tangential discharge therefrom.

10. The impeller means defined in claim 9, in which the blades have outer portions which extend outwardly relatively short distances from the peripheries of said members, and said outer offset leading surfaces are provided on angularly disposed elements which are respectively jointly carried by said outer portions of said members for finally directing the product in predetermined directions at the locations of discharge.

11. The impeller means defined in claim 9, in which said blades are respectively provided with tip elements having leading surfaces which are disposed at angles of substantially with reference to diametrical lines of said impeller means.

12. The impeller means defined in claim 9, in which said central opening in said one member is defined by a truncated tubular conical portion which has a larger cross-sectional dimension adjacent to the product receiving area than outwardly therefrom, and the other member is provided with a relatively thick central portion for attachment to a rotary shaft.

13. An impeller means adapted for use with a cutter assembly having eircumferentially spaced knives, said impeller means comprising a pair of planar annular members fixedly secured together in an axial predetermined spaced parallel relationship by a plurality of circumferentially spaced blades, one of said members being provided with an opening through which a product to be comminuted may be introduced into the impeller means, and said blades being disposed in generally chordal positions and being provided with outer leading surfaces which face in the direction of the impellers rotation and with inner leading surfaces for causing an introduced product to travel outwardly in advance of said outer surfaces for engagement thereby whereby the latter direct the product against the knives ofa cutter assembly when utilized in conjunction therewith as compared to radially disposed blades.

14. In combination: a cutter assembly and impeller means; said cutter assembly comprising a plurality of eircumferentially spaced knives; said impeller means being disposed in said cutter assembly and comprising a pair of round planar members joined together by a plurality of eircumferentially spaced blades defining in internal central product receiving area, one of said members being provided with a truncated tubular conical portion; and a cover having a tube through which a product may be introduced into said receiving area via said conical portion for direction by said impeller means against said knives for comminuting the prod uct, said tube having an end disposed in said conical portion.

15. The combination defined in claim 14, including structure supporting said cutter assembly, means for clamping said cutter assembly to said supporting structure, a guide disposed about said cutter assembly, said impeller means and said supporting structure through which the comminuted product is discharged, and means common to said cover and said guide for detachably holding them in relation to said supporting structure.

16. A method of comminuting a product which comprises rotating the product by an impeller having inner and outer surfaces facing in the direction of the impellers rotation whereby the inner surfaces cause the product to travel outwardly in advance of the outer surfaces so that the latter engage and direct the product outwardly against cutting edges provided on a plurality of backwardly tilted circumferentially spaced knives for comminuting the product into fine particles of substantially uniform size and flow of the particles outwardly between the knives in directions opposite to that of the impellers rotation.

17. A cutter assembly for use with an impeller adapted for rotation therein, said assembly comprising a pair of rings respectively provided with a plurality of eircumferentially spaced seats, a plurality of axially extending eircumferentially arranged closely spaced rectangular knives tilted backwardly relative to an impel lers rotation and having ends disposed in said seats and spacing said rings apart in parallel relation, means securing said rings together for locking said knives in said seats, said knives being respectively provided with inner relatively narrow longitudinally extending rectangular faces and a pair of rectangular parallel side faces which extend outwardly from said inner faces so that the inner face and one of the side faces of each knife defines an axially extending cutting edge and the opposed side faces of adjacent knives define backwardly tilted spaces therebetween whereby a product when rotated by an impeller will be caused to engage said cutting edges for comminuting it into fine particles of substantially uniform size for flow outwardly through said spaces, while substantially avoiding said inner faces whereby to substantially prevent accumulation of deposits thereon. 

1. IN COMBINATION: A CUTTER ASSEMBLY HAVING A PLURALITY OF CIRCUMFERENTIALLY SPACED KNIVES HAVING INNER CUTTING EDGES AND IMPELLER MEANS COMPRISING A PAIR OF SUBSTANTIALLY ROUND PLANAR MEMBERS, A PLURALITY OF CIRCUMFERENTIALLY SPACED BLADES INTERPOSED BETWEEN AND CARRIED BY SAID MEMBERS, SAID BLADES HAVING INNER LEADING SURFACES DISPOSED WITHIN THE CONFINES OF SAID IMPELLER MEANS AND WITH OUTER LEADING SURFACES EXTENDING OUTWARDLY AND FORWARDLY AT AN ANGLE WITH REFERENCE TO SAID INNER SURFACES FOR DIRECTING A PRODUCT INTRODUCED INTO THE IMPELLER MEANS AGAINST SAID CUTTING EDGES, AND SAID KNIVES ALSO HAVING OUTWARDLY EXTENDING SURFACES AND INNER FACES WHICH ARE DISPOSED TO PROVIDE CLEARANCE WHEREBY THEPRODUCT IS CAUSED TO FIRST SUBSTANTIALLY ENGAGE SAID CUTTING EDGES FOR CUTTING THE PRODUCT INTO FINE PARTICLES AND SO THAT THE LATTER WILL FLOW OUTWARDLY BETWEEN SAID KNIVES VIA SAID EXTENDING SURFACES AND SUBSTANTIALLY AVOID ENGAGING SAID INNER FACES.
 2. The combination defined in claim 1, in which said outwardly extending surfaces adjacent said cutting edges are inclined rearwardly.
 3. In combination: a cutter assembly and an impeller means disposed therein for rotation, said cutter assembly comprising a plurality of circumferentially spaced knives, said impeller means comprising a pair of planar round members and a plurality of spaced blades joining said members at circumferentially spaced locations and defining in combination with said members an internal product receiving area, one of said members being provided with a central opening through which a product may be introduced into said receiving area, and said blades being respectively provided with concave leading surfaces and with leading surfaces facing in the direction of the impellers rotation which extend outwardly with reference to said concave surfaces whereby to cause the product to travel for substantially maximum tangential discharge from said impeller means against said knives for comminuting the product for flow outwardly from said assembly through the spaces between said knives.
 4. In combination: a cutter assembly having a plurality of circumferentially spaced knives provided with relatively large outwardly extending surfaces and inner smaller surfaces defining cutting edges and impeller means comprising a pair of planar round members and a plurality of spaced blades joining said members at circumferentially spaced locations and defining in combination with said members an internal product receiving area, one of said members being provided with a central opening through which a product may be introduced into said receiving area, and said blades being respectively provided with concave leading surfaces and outer surfaces extending outwardly with reference to said concave surfaces and facing in the direction of the impellers rotation whereby the product upon rotation by said impeller means will be caused to engage said cutting edges for cutting the product into fine particles for discharge outwardly along said extending surfaces and between the spaces between the knives and free of the cutter assembly without substantially engaging said inner surfaces.
 5. In combination: a cutter assembly and an impeller disposed therein for rotation, said cutter assembly comprising a plurality of circumferentially spaced knives provided with inner cutting edges and with outwardly extending surfaces which are tipped backwardly with reSpect to the impellers rotation, said impeller comprising a pair of planar round members and a plurality of spaced blades joining said members at circumferentially spaced locations and defining in combination with said members an internal product receiving area, one of said members being provided with a central opening through which a product may be introduced into said receiving area, and said blades being respectively provided with leading surfaces which are curved in the direction of rotation and with leading planar surfaces which extend outwardly with reference to said curved surfaces and face in the direction of the impellers rotation whereby to cause the product to travel substantially tangentially against said cutting edges for comminuting the product into fine particles of substantially uniform size for flow outwardly along said extending surfaces and through the spaces between said knives from said cutter assembly.
 6. In combination: a cutter assembly and an impeller disposed therein for rotation, said cutter assembly comprising a plurality of circumferentially spaced knives which have inner cutting edges and outer portions which are tipped backwardly with respect to that of the impellers rotation, said impeller comprising a pair of planar round members and a plurality of blades joining said members at circumferentially spaced locations and defining in combination with said members an internal product receiving area, one of said members being provided with a central opening through which a product may be introduced into said receiving area, and said blades being respectively provided with outer leading surfaces which face in the direction of the impellers rotation and with inner leading surfaces for causing an introduced product to travel outwardly in advance of said outer surfaces for engagement thereby whereby the latter direct the product against said cutting edges for comminuting the product into fine particles for flow outwardly through the spaces between said knives.
 7. The combination defined in claim 6, in which said knives are provided with inner faces disposed to provide clearance so that the product will substantially only engage said cutting edges and avoid said inner faces.
 8. In combination: a cutter assembly and an impeller disposed therein for rotation, said cutter assembly comprising a plurality of circumferentially spaced knives which have inner cutting edges and outer portions which are tipped backwardly with respect to that of the impellers rotation, said impeller comprising a pair of planar round members and a plurality of blades joining said members at circumferentially spaced locations and defining in combination with said members an internal product receiving area, said blades having outer portions which extend outwardly relatively short predetermined distances from the peripheries of said members and said members are provided with portions which also extend outwardly beyond their peripheries for supporting and reinforcing said outer portions of said blades, one of said members being provided with a central opening through which a product may be introduced into said receiving area, and said blades being respectively provided with leading concave surfaces which are curved forwardly with respect to the impellers rotation whereby to cause all of an introduction product to first travel on said leading surfaces and then substantially directly against said cutting edges for comminuting the product into fine particles for flow outwardly through the spaces between said knives.
 9. Am impeller means adapted for use with a cutter head to assist in comminuting a product, said impeller means comprising a pair of planar round members and a plurality of blades joining said members at circumferentially spaced locations and defining in combination with said members an internal product receiving area, one of said members being provided with a central opening through which a product may be introduced into said area, and said blades being respEctively provided with inner surfaces which are curved in the direction the impeller means rotates and with outer offset leading surfaces extending outwardly with reference to the periphery of said impeller means whereby an introduced product upon rotation of said impeller means will be caused to travel outwardly in paths successively along said curved and offset surfaces for substantially maximum tangential discharge therefrom.
 10. The impeller means defined in claim 9, in which the blades have outer portions which extend outwardly relatively short distances from the peripheries of said members, and said outer offset leading surfaces are provided on angularly disposed elements which are respectively jointly carried by said outer portions of said members for finally directing the product in predetermined directions at the locations of discharge.
 11. The impeller means defined in claim 9, in which said blades are respectively provided with tip elements having leading surfaces which are disposed at angles of substantially 10* with reference to diametrical lines of said impeller means.
 12. The impeller means defined in claim 9, in which said central opening in said one member is defined by a truncated tubular conical portion which has a larger cross-sectional dimension adjacent to the product receiving area than outwardly therefrom, and the other member is provided with a relatively thick central portion for attachment to a rotary shaft.
 13. An impeller means adapted for use with a cutter assembly having circumferentially spaced knives, said impeller means comprising a pair of planar annular members fixedly secured together in an axial predetermined spaced parallel relationship by a plurality of circumferentially spaced blades, one of said members being provided with an opening through which a product to be comminuted may be introduced into the impeller means, and said blades being disposed in generally chordal positions and being provided with outer leading surfaces which face in the direction of the impellers rotation and with inner leading surfaces for causing an introduced product to travel outwardly in advance of said outer surfaces for engagement thereby whereby the latter direct the product against the knives of a cutter assembly when utilized in conjunction therewith as compared to radially disposed blades.
 14. In combination: a cutter assembly and impeller means; said cutter assembly comprising a plurality of circumferentially spaced knives; said impeller means being disposed in said cutter assembly and comprising a pair of round planar members joined together by a plurality of circumferentially spaced blades defining in internal central product receiving area, one of said members being provided with a truncated tubular conical portion; and a cover having a tube through which a product may be introduced into said receiving area via said conical portion for direction by said impeller means against said knives for comminuting the product, said tube having an end disposed in said conical portion.
 15. The combination defined in claim 14, including structure supporting said cutter assembly, means for clamping said cutter assembly to said supporting structure, a guide disposed about said cutter assembly, said impeller means and said supporting structure through which the comminuted product is discharged, and means common to said cover and said guide for detachably holding them in relation to said supporting structure.
 16. A method of comminuting a product which comprises rotating the product by an impeller having inner and outer surfaces facing in the direction of the impellers rotation whereby the inner surfaces cause the product to travel outwardly in advance of the outer surfaces so that the latter engage and direct the product outwardly against cutting edges provided on a plurality of backwardly tilted circumferentially spaced knives for comminuting the product into fine particles of substantially uniform size and flow of the particles outwardly between the knives in directions opposite to that of the impellers rotation.
 17. A cutter assembly for use with an impeller adapted for rotation therein, said assembly comprising a pair of rings respectively provided with a plurality of circumferentially spaced seats, a plurality of axially extending circumferentially arranged closely spaced rectangular knives tilted backwardly relative to an impellers rotation and having ends disposed in said seats and spacing said rings apart in parallel relation, means securing said rings together for locking said knives in said seats, said knives being respectively provided with inner relatively narrow longitudinally extending rectangular faces and a pair of rectangular parallel side faces which extend outwardly from said inner faces so that the inner face and one of the side faces of each knife defines an axially extending cutting edge and the opposed side faces of adjacent knives define backwardly tilted spaces therebetween whereby a product when rotated by an impeller will be caused to engage said cutting edges for comminuting it into fine particles of substantially uniform size for flow outwardly through said spaces, while substantially avoiding said inner faces whereby to substantially prevent accumulation of deposits thereon. 